Telephone exchange system



1933. J. B. NEWSOM TELEPHONE EXCHANGE SYSTEM 15 Sheets-Sheet 1 Filed March 18, 1932 Nmn awn 3m QR Sat tat 52k W 3 2m 9 2. 99k J ATTORNEY Feb. 14, 1933. J B NEWSOM 1,897,069

TELEPHONE EXCHANGE SYSTEM Filed March 18, 1932 15 Sheets-Sheet 2 \1 9' i m I a w lNl/ENTOR a Q BYJ. B. NEWSOM mam A T TORNEV J. B. NEWSOM TELEPHONE EXCHANGE SYSTEM Filed March 18, 1932 15 Sheets-Sheet 3 llllllllllllll llllllll I ll IE MGM ATTORNEY Feb. 14, 1933.

0mm lUD -D O UD AYLU Au: nIoAU Di n Nbm no 3Q 93 e3 5 Feb. 14, 1933. J. B. NEWsoM TELEPHONE EXCHANGE SYSTEM Filed March 18, 1952 15 Sheets-Sheet 4 INVENTOR J. B. NEWSOM A TTORNEV Feb. 14, 1933. J NEWSOM 1,897,069

TELEPHONE EXCHANGE SYSTEM Filed March 18, 1932 15 Sheets-Sheet 5 lNl ENTOR v J. 8. NE WSOM ATTORNELV Feb. 14, 1933.

J. B. NEWSOM TELEPHONE EXCHANGE SYSTEM Filed March 18, 1932 15 h h 5 IN 5 N TOR By J. B. NEWSOM ATTORNEY Feb 14, 1933. J.-B NEWSOM 1,897,069

TELEPHONE EXCHANGE SYSTEM Filed March 18, 1932 15 Sheets-Sheet 7 IN VENTOR J B. NEWSOM A 770 R/VEY J. B. NEWSOM 1,897,069

TELEPHONE EXCHANGE SYSTEM Filed March. 18, 1932 15 Sheets-Sheet 8 Feb. 14, 1933.

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TELEPHONE EXCHANGE SYSTEM Filed March 18, 1932 15 Sheets-Sheet 9 INVENTOR y .1 8. NE WSOM A T TORNEV FIG. 9

Feb. 14, 1933. J. wsQ

TELEPHONE EXCHANGE SYSTEM I Filed March 18, 1932 15 Sheets-Sheet 10 IN l/EN TOP .1 8. NE WSOM A TTORNE) Feb. 14, 1933. J, NEWSQM I 1,897,069

' TELEPHONE EXCHANGE SYSTEM Filed March 18, 1952 15 sheetssheet 11 INVENTOR By J BNEWSOM ATTORNEY Feb. 14, 1933.

J. B. NEWSOM TELEPHONE EXCHANGE SYSTEM Filed March 18, 1932 15 Sheets-Sheet 12 PTvN hI-N INl J BNEWSOM 5) ATTORNEY Feb. 14, 1933. J B, NEWSOM TELEPHONE EXCHANGE SYSTEM Filed March 18, 1952 15 Sheets-Sheet 15 M N ma J.

A 7'7'ORNEY Feb J. B. NEWSOM TELEPHONE EXCHANGE SYSTEM Filed March 18, 1932 15 Sheets-Sheet l4 M R0 M w a J A TT'ORNEV Feb. 14, 1933. J. B. NEWSOM TELEPHONE EXCHANGE SYSTEM Filed March 18, 1932 15 Sheets-Sheet 15 E v N 8 J W mvfi v3 .3 6t

ATTORNEY Patented Feb. 14, 1933- UNITED-STATES PATENT OFFICE:

JAMES B. OF GREAT NECK, NEW YORKQASSIGNOR TO BELL TELEPHONE- LABORATORIES, INCORPORATED, OF NEW YORK, N. Y.,'A CORPORATION OF NEW YORK Applicationii led narch.18, 1932. Serial No. 599,611.

5 Thisinventionrelatesto a dial switching telephone system and more particularly to a district selector. link circuit for enabling an operator at a dial'switchi'ng A switchboard toiextendconnections from her switchboard through thecaid of afsender'acc'essible to the linkcircuits, The object of the in ention s to enable the transmission of a recorder signaltothej operator the event that'difiiculty islencountered eithe'rfin thejsele'ctor switches oriin'ithe sender to establish a connection,'so'th at th'eopeijator may take down the par i lvf s li h onn cti 39d} t to establish anewicon iectiom I I v n a a sw t hi i l rhb y em in. which the present i'liventionfis "designed to be employed, icalls'may arrive requiring the: assistance of an'o' erato'r, 'Such callsare automatically route" to an operators position, at which position are cor d circuits foranswering suchicalls... Thebperator'iipon receiving such'a'call'a'nd answerin' it with'one of the cord circuits'of her position, 'asc'ertains from the calling subscriber the number of the line desired." She then plugs the calling end of the cord circuit ,into the jack ofa trunk circuit of the proper character for terminating the desiredjconnection. If, for'example, the desired-line terminatesin another oflice' of the exchange area, the trunkcircuit which the operator selects will terminate'i'n a district selector, I

The trunk circuitor district selector link circuit in accordance ,.with the present invention, .is provided with a sender selector switch which'isstarted as soon as the operator plugs'into the jack of the trunk circuit and associates the trunk circuit with an idle sender. The operators position may) be equipped with a calling dial or a keyset for causing the registration of a desired line number'injthe sender." In the present embodiment of, the invention, the-operators position equipment disclosed is provided with. a ten button keyset and accordingly the sender is arranged to be 'controlled'from the keyset. A sender of this type is disclosed in the copending application of W. B. Strickler, Serial No. 599,684, filed March 18, 1932.

After the operator has plugged a cord circuit into the trunk circuit, with her talking keystill thrown, her keyset becomes asso'- ciated overthe tip and ring condueto'rsof the. cord circuit and trunk'circuit with the sender as soon as she operates herkeyset key.

operator to reestablish the connection because of the failure of apparatus used to function properly. 4 H

Should it become necessary to signal the operator to reestablish a connection, this can only be done after herdial or keys'et has been disconnected from the cord circuit since the supervisory relay of the cord circuit is not connected over the calling plug of the cord circuit while the dial or keyset is connected. The necessity for giving the operator a reorder signal may arise because of one of several conditions; 1 In the establishment of a desired connection the district selector may, in hunting for an idle trunk extending to the oflice of the desired subscriber, or in hunting for an idle oiiice selector, find all such trunks busy and thus advance its brushes to an over flow position in its bank, or the ofiice or incoming selector similarly may find'no free outgoing trunk in the desired group outgoing therefrom and advance to an overflow position, or the district selector may not be arrested properly in its brush or group selection movements and thus advance to the telltale position at the top of the terminalbank,

or other selectors employed may-advance to tell-tale or overflow positions, or the sender may fail to advance properly, or the oper-,

lamp of the cord circuit is flashedias a re order signal. H The manner in which the invention' fun'c tiers .wi l, be, more evi en f om, .the, ol ow: in}; "detail 'de'scfiptionltalien inv {connection wi hithei ewmi m y il d ew ig hic an ,bpeiatorf's cord circuit for, speaamer i e n nt rc pfi i -m,1 at, rrrrniates in a d strict selector-anda ends lfi fie't b conn t ng. he-t ucke lfdlesenderi andi e rh maae H 1 fis act r e l he secret co danc'e with digits jregistered H i 4 nderl an, other control relays; V 5: i5,','6, d l we ieg .s r

er. egis erin d s iiedu y bp r addit' m1 control 'iielaysg,v i 4 established; v v & 12shows a steering or sender; control se uence switch;

13. shows control relays;

' Figs. 14 and 15 show the selection controlo lin regis'ter sand additional control relays; 5 an f "FigJlG is a diagram showing the manner in which thfinlf m -lning figures should be arrangedtoshow the complete circuit.

The cord circuit of Fig. 1 located at the A? operatorsswitchboard position has access over the answering plug shown at the lefit'of the figure to jacks of incoming trunks, which trunks may, for examp le,' be intercep tingtrunks from final selector or incom- 59; ing} selector multiples or special service t'runks'over which calling subscribers may obtain connection with the A? switchboard operators position for the purposeof obtaining the assistance of' the operator in completingtol'lor other calls. The operators comingiselector switches for terminating toll calls, the trunks of a second group terminating in offic"selectors of a distant office and the t n at a third green t rm aa in y d s ric 5 r l0i a".d a t t idtm fee.- The-sender jdisclo d 'imFigsre tolfiinusiyefis Tsim'i tfJi, n rate the. sender f lbj fedki'xi' th me t;jqfssay ondaand 1?, No; 1 862,549; a e u ee, 932, t e. i eni 161 appl' tbinp te ei, Qnianemn(wahihede d r anddecoder nn 6 r'disclosedin detail in d L a c nna-at i e de ode mnpat'e'ut im ii gqo l i. 1; v "It will. be ass mdith an incbming nection is extendedl'in any Well-known mannegro the trunk j ckgloo orgEi lffand. that the desiredf connection. may be completed over; the trunk circuit fofljigi .3 The opera t'or fupjon' noting thefilliiii inationof the lamp ductive winding 104of relayi 103. At the.

same time the trunk lamp. is extinguished. Relays 102 c and 103. both; operate over a, low resistance ground connected to the sleeves of trunks employed for special service and establish a circuit for the supervisory lamp 105extending from battery over the inner contact of relay 102-, resistance .106, back contact of relay 107, backcontact, of. relay 108' to ground through lamp 105 and in parallel therewith from'batteryover. the inner contact .of'relayj102, resistanoelOfi, back contact of: relay 107, backcontact of relay 108, innerlower back contact, of relay 109,, inner normal contacts and winding ofrelayj 1 10 to P a hiev s-r ht norma cnta winer es 9 .026 key 111,;- Relay 1l0-locks gin, a circuit from i ,battery at the inner contact;ofzrelayv 102, inner upper alternate contacts. and Winding ofrelay 110- t groundat 'key 111.,

inner upper frontcont'aot of re1ayi103, lower winding of relay 107 to ground-through ballast lamp -115.-. -Relay ;107 operates and a flashing-shunt circuit' is thereupon establis'hed for'lamp 105" until the-operator throws. key 111 to the right to unlock relay 110 whichcircuit may be traced from; ground through i lamp 105, back contact of relay-108, vfront contact of relay 107,'-l0wer' front contact of relay'110 torground at the "contacts-{of interrupter 116; In case,-.-however, relay 107 -operatesbefore relayl110 c'anoperate, lamp "105 does not lightz Theipossible flashing of lamp'=-105 as above described is incidental and has no significance'atithis:timd Z2 cuit is established from When the operator throws-lierfkeydfl to the right ortalking position, an obvious'ciround over the upper right-contactof key 111 for:' relay 117 "whichfestablishes'a circuit from ground at the upper front con'tact'of relay-r103, inner upperfront'contact of relay 117, conductor 1 18 to battery through the upp'er 5 winding jof'relay 200'.'-Re1a 200 operates'and a talk- 1 ing path is thereupon established-"from the "upper right winding of repeatin-g coil 113,

inner upper right contact of key 111,--con-' doctor 119, upper contact of relay'200, right windingof repeating coil 201, condenser 202, lower contact 'of'relay'200, conductor-120, inner lower right contact (if key 111 to the lower right winding of coil 113.- Assuming that the operators telephone set .203 is plugged up, the talking pa'th just traced is inductively associated therewith through the leftfwinding of repeating coil 201 and the operator is thereupon enabled to converse with the calling"subscriber to ascertain in- 1 formation concerning the desired connection.

It will be'assumedthat thedesired connection is of a character which is'to be completed over a district selector such as is shown in "Fig. 3 and that therefore the operator first tests for an idle trunk of a group terminating in a district selector switch by testing the tip of calling plug 121 to the sleeve of the jack of a trunk of that group. If the trunk is busy there will be battery potential on the sleeve and this potential will be transmitted over the tip of plug 121, the upper normal contacts of relay 122, the inner upper back contact of relay 123, the upper norwinding of repeating coil 205, which induces the busy potential through the left winding of coil 205 into the operators telephone set, thus .producing a click in her receiver. As-

suming that she tests the trunk circuitlof 1 Fig. ,3 and findsit, idleand receivesno click,

she inserts the plug 121 into jack 302 thereby establishing a circuit extending from ground, Winding of relay 300, the lower left and upper right contacts of cam 301, the sleeves of jack 302 and plug 121, windings of relay 126 and marginal relay 127 in series to battery and in parallel therewith. through resistance 128 to battery. ue; to the resistance of sleeverelay 300 of thet'runk circuit, suiiicient current flows through the winding of relay 126 to cause its. operation, but marginal relay 127 does not operate Relay 300 operates and locks 'overfi'ts upper front contact directly to the sleeve of jack 302 and prepares a circuit. for lightingthe group busy lamp 303 when all trunks offthe group are busy. Relay 126 upon operating closes a circuit extending from battery over its lower contact, the lower normal contact of key124 to groundthrough the winding of relay 123 which operates, opening the busy test circuit at itsupperback contact'and at; its inner upper and inner lower front contacts connects the tip and ringi contacts of plug 121 to the right windings of repeating 'coil 113. Relay 126 at its lowerfrontcontact also establishes a circuit for la1np 129, extendingover the upper back contact of .re-

blay 130. Preparatory to keying the digits necessary to complete the connection, the operator now depresses the key .206 and, with the talking key 111 operated to the right, a circuit is established from ground at the lower back contact of relay 208, the right contacts of key 206, conductor 207. the lower and upper intermediate alternatecontacts of key 111, the upper winding of relay 122 to battery at the lower contact of relay 123. Relay 122 thereupon operates and locks in a circuit from battery over the lower contact of relay 123, lower winding and inner front contact of relay 122, conductor131, back con-- tact of relay 209 and in parallel toground through resistance 210- and the winding of relay 208. Relay 208 operates in this circuit opening the initial operating circuit of relay 122 and closing an obvious circuit for, relay 211 which operates. Relay 122. at-its upper and lower alternate contacts, disconnects the tip and ring contacts of plug 121 from the right windings of-repeating coil 113, and connects these contacts over conductors 132 and 133 with the operators keyset circuit.

Relay 2111 upon operating closes an obvious circuit to light lamp 212,connects ground over conductor 213 for supplying operating 'ii peralaianae contacts of relay122, a s of 308'fihrier upper back"contact of relay 309, '"rom batteryon conductor 316. overbrush za85 t at uster rant contact-bf Q plug '121 iindfiwk1302j upper contacts cam "5305, to battery throughkthe winding of start relay 304 'Relay 304ope'rates, but due to v 'gh resistance of its winding, relay 215 92aw r-keyaqcircuit does not receive sufii- I cientjiciirrent: to operate.

.f r'elayf300 bp rateamlose a cii cuit from bat-- I relay 318 whi'ch- -releases opening the {circuit {of magnet 32O which in'turn' releasesand-advances the -brushes-of-switcli 3'50- one step.

In this manner -through the alternateloperation'andr'elea'se-o'f relay 318: and magnet320,=

the-brushes of switch-350- are advanced step by step'until=test brush 366 engages the-ter- 1 niinal of anidle sender; when the 7 previously traced Icircuitthrough the upper and lower '-==windings-cf test "relay 314 tothe testtbrush' -fRelay 304,;with

" 366' will be completed; for example, over con i ductor 316-,"inner: right back' contactrof reit yi li g f "winding 'of"relay" 306, contact of lay 1000yfleft backi contact. of: relay 1001;;t0

.conductorl 363 to "ground at the' fr'elay 300, relay'soslupon operiltinglockingover'its upper wind "ingiandinner upper-front contact, lower "left 'ai'i'diupper right'contact' sfof cam 307,

uppefiight and' lower "left contacts of cam i, conductor sca red closing a cir-f curd-extendin from battery, winding of battery lthrough resistance 1002. Relay: E31 1 now'=rece1ves= sufiicient current to operate and =1 atr its 'lower back conta'ct'iopensithe circuit f relay :313 'wh'ich releases and opens the circuit of stepping 'rel'ay 318 toi-a-rrest further movement-of switchv350; iRela-y'z 314 looks 366, upper contacts of: cam :317; upper windingfandiupper front c0ntact;o-relay3-14, up-

Eihagnet-310 ,i'contact of (mm '311; upper left-' per rightiand lowerle'ft contacts of =cam 308,

lcoiltact of 312," to ground at the upper fiont' contact of relay -306,"ft'hus advancing u ppei'back contact: of relay. 309; t0rrgr011nd I V p on-conductors363? 'Theincreasedpotentialz90 6' i s quen'cetwi'tch 310into-po'sition 2. Uponon thecsenden-testwconductor 316 marks :the

senderraszbusy-rto othensenderselectors. 7: Relay 3135111) on 1 releasing 13180 closes acircuit lay 313 operates in a ciruit'extending fro1n" of'cam 322','-uppe1-.-ba ck: contact-of relay [313,

j 'fba tterythrgiiigh its winding, lowerback contact of test{relay 314}; left contacts of cam- 308', inner upper back contactof relay 309, to

" contacts jrl yeis' bnaect thd=w0 lowerw indings:ofjtestrelay "3,14 in aseries circuit 'e iitending'"from battery throughthe middle windihgofirela 31;, lower contacts'of relay 5 f at the :lefticontacts'of earn 315 thereby pre-=-' "paring thefmarginal test relay 314 for opera-i "Ztion,'and' connectsthe test brush'366 of se'nder Selector .350 over the upper 5 contacts of {cam- "loWe-fiWindingJ of marginal relay309 to 'the lower left contact 'of icain 367 and from Bat- 314; toiground'r'tery througli ithe :w inding -of sensitive relay 324 to-the lower right-contactoficam 367 and thence "over the upper 'left contact rof :cam 367,- inner-lower front contact of relay 300, left contacts ofcam 325, brush 326 conduotor 317, 'upperyvindingof relay 314, lower con- "a321-and windings 0t relay 500 .of-thesender tacts of relay 313,'loWer'Winding' of relay and thence astraced to ground at cam 315.

It will" first" he nssuiiied that the sender J upon the 'ter'in'iiialsof which the brushes ofselector 350m atthe' time standing is'liusyandthat no" operating circuit is therefore" closed for relay 314, A'circ'uit is thereforeclosed fromhatteryywindingof stepping re.- lay 318, lower contacts of a1n'369, hack contact of 's'tepping'magnet 320, upper front contact of relay 313,' upper ba-ck contact of test relay 314; up'per righta'nd lower left contacts of cam 308, upper back contact of relay 309 to ground on conductor 363; Relay 318 op crates connectingthe winding of stepping magnet 320 in a'circuit eiqtendi'ng over the upper contacts of cam 368, upper'frontcon- 'closes anobviouscircuit for relay- 327 which locks-over its inner lower front contactand the right contacts-of cam 328 to ground after sequence'switch 310 reaches position 11 and until itleaves position 1 1.

Relay 500 upon operating closes an obvi-v ous circuit over conductor 501 for relay 700 which in-turn causes the operation of .relay 1302' over conductor 701 andconnects battery to the off-normal battery conductor702.

Relay 1302 upon operating connects ground from its outer right front contact to the oil'- normal' ground-conductor 1303 thereby caustact of relay 318' to ground over the operat--- 'ing the operation of relay 1001 which in ing circuit of 'relay'318, whereupon'rnagnet 55 320 energizes in'turn opening the circuit of turn "*rem'oves' battery through resistance 1002 fromconducto'r 316 to mark the sender 1100 exten ds' aover' conductor' 1101-, ithezinner -left back contact. of relayu90l, to conductor 1303 and the operating circuit of relay'1304 extends over the' 'backficontact of relay 1305,

toconductor 1303, r;elays%'1100 and 1304 both;

operating; :circuit-L is'r also; closed from ground: on-(onducfiorj1303; left contacts of;

cam l2 02',"conductor 1203,:lhft-back contact?- of relay -1306','.cond-uc'tor 13074130 battery'- through the left winding Iof re1ay,1400. The operation; of relay 1400 at this timeapr'events 255 the sender control switchv1200 from moving oifnormal if-zthe call(is'sabandoned before selections are startednl :Neither of flbheatrunk class register relays- 900 or- 905 operates-forthis type of callandicorisequently relays- 902,- ,Z

903; 911,'1306',E-1500rand'1501:?do notmpera'tetrunk conductor 334, rings ofjack 302 and i With relay 1001 l operatedand "relay -900- not operated. a "circuit is: i'establislied from battery, windings of-transfer relays -511- and 355 514, in series, back contact :of relay ;515-, conductor 516, ibackcontact' of relay 2900,; con--- ductor 906, inner rightback contact of relay 505,'=conductor 506, inn'errleftfront contact of relay 1001' to grounds-Relays: =5111andz514 i403 lock in series over" the back: contact of relay 515, conductor 516',back contact'of relay 900, conductor 906, outer rightHfrontcontactof relay 511, conductor. 506'ito ground. The operation ofutransferf relays 5'1-1-and 514 indicates that the first'digit' keyed by theoperator will be registered on the first -or A code register. :With relay 511 operated-,wacircuit is established for relay 505-;extending from battery; windingof' relay 505,1 conductor 517 rightfrontcontact of relay 511, conductor 506, to ground at the. front contact of relay 1001. At its rightback contact, relay 505 opens the'initial operating circuit of relays 511 and 514. When relay 1300 oper ates as previously described, the 'funda-mem:

tal tip conductor 319 and the-fundamental ring conductor 323 are disconnected from the windings of the trunk class register relays 900 and 905 and these conductors are thereb made free for'fundamental selections.

Withsequence switch 310 in position 4, a circuit is extended from battery through re sistance 216,.the upper normal contacts of relay 217, conductor 133, the lower alternate contacts of relay122, the-ringsof plug 121,

and jack 302, trunk conductor 334,. the upper.

cuit from ground at the upper contact of relay-211, upper normal contacts andwind v ing of relay 215', conductor 132, upper alter nate'contacts of relay 122,1tips of, plug 121 and jack 302, trunk conductor.370, .upper, right and lower left contacts of'cam-.305 brush 333, conductor 329, inner left backgcon-g tact of relay 406, the outer left front contact;- of relay 407, in series throughthewindingsg i of impulse relays 411, 412 and 413,.conduca'. tor 414- and the outer left front contact .off. relay. 505 to 24-volt battery. Relay 407;also establishes a circuit from 24-volt battery 5' thefsenderover the inner left front contact of relay 505, conductor 424 through the windings of impulse relays 421, 422 and 423, the, inner left front contact of relay 407, the: right back contactof' relay 4 06, conductor. 332, brush 366, the upper contacts of earn 335, j

plug 121, lower alternate contacts of relay 122, to conductor 133 extendingto the oper-= ators keyset. U i 1: v -Rela-y 215 operates in the circuit previously 9- traced looking over its upper alternate; con-g; tacts to battery through resistance 216 under the control of-relay 211 and .closes a circuit; from ground at the upper contact 30f. relay. 211, upper back contact of relay. 1 218, lower contact of relay} 215, to battery through the winding of relay 217. Re-- lay 217 upon operating connects 48 volt battery through resistance 219and the lower front contact of relay 217, to conductor 220 for supplying battery to key contacts of keyset 214 and connects the keyset over its inner lower front and upper alternate contacts and conductors 132 and 133 to the tip and ring impulsing conductors 329 and 332 as previously described. Relay 215 also closes a circuit extending from ground at theupper contact of relay 211, upper back-contact of relay 218, lower front contact of relay 215, lower back contact of relay 218, to battery through lamp 221. Lamp 221 lights as an indication that the sender is in condition to receive the digits of a line designation.

Keying the ofliee code 

